James Fleet


Foods and Nutrition


Nutrition Science


calcium, genetics, diet, bone, mouse


Both dietary calcium and genetics influence bone density and structure. However, how genetics

affect the adaptation response of bone parameters to dietary calcium (Ca) restriction is unknown.

11 inbred strains of mice were fed adequate (0.5%) or low (0.25%) Ca diets from 4-12 weeks of

age and were evaluated for gene-by-diet interactions affecting bone structure at the femur and

lumbar spine. We observed that genetics and diet main effects as well as gene-by-diet

interactions significantly affected femur trabecular and cortical bone, and lumbar spine

trabecular bone microCT parameters. There were no significant correlations between basal and

adaptation parameters in femur or lumbar spine. Adaptation of lumbar spine trabecular bone

parameters was smaller compared to adaptation observed in the femur trabecular bone. However,

the adaptation parameters in these two bone sites were significantly and positively correlated.

We conclude that (1) genetic controls of basal and adaptive bone parameters are distinct; (2)

trabecular bone in lumbar spine is more resistant to calcium restriction than the trabecular bone

in distal femur; (3) similar genetic forces affect the adaptation response in distal femur and

lumbar spine trabecular bone. However, site-specific regulation may exist in bone structure

adaptation response to calcium restriction in some of the inbred lines.